The present invention relates to a golf club head, more particularly to a reinforcing structure for the sole portion provided with a separate weight member.
In recent years, wood-type hollow club heads for drivers and the like are increased in the volume, while preventing the weight from increasing. Accordingly, there is a tendency that the wall thickness of the sole portion becomes decreased like the other portions of the head.
On the other hand, in the golfers especially average golfers, there are great demands for golf club heads with a low and deep center of gravity to produce a high launch angel with low spin for longer and straight drives.
In the U.S. Pat. No. 7,101,291, a wood-type hollow golf club head is disclosed, wherein a tubular socket is integrally provided on the inside of the sole portion, and a weight member is secured in the socket. In such a structure, if the mass of the weight member is increased in order to lower and deepen the center of gravity of the head, as the tubular socket protrudes relatively high into the hollow of the head and the socket is filled with a heavy metal, the socket is vibrated when striking a ball, especially when duffing a ball, and a large stress acts on the vicinity of the socket. Thus, such a vicinity zone becomes a weak point, and in the worst case, a crack is caused in the vicinity zone. As a result, the adjustable range of the position of the center of gravity of the head is limited and it becomes difficult to set the center of gravity at the desired position because it is necessary to limit the mass of the weight member not to cause a large stress.